Hello Willem,
Congrats, that's a definitely a sweet one! (Please keep me posted if you ever decide to let it go - I've some of its family members waiting here...
)
I'm not fully convinced that this is an "alang" rather than a smallish "panjang" though. What's the length with and without hilt? OTOH, with 66cm for a panjang and 61cm for an alang (examples shown in vZ), I'm not sure wether there actually is any clear cutoff in size... Since alang is supposed to denote those pieces which were "too short for warfare" and, thus, mainly for ceremonial use, this may also have been a personal decision rather than being a clearcut classification.
I understand that Luju Alang is the Gayo name for this sword type. The ink decoration on your scabbard (and possibly the crown on the hilt, too?) does look more Aceh to me. Thus, calling it Sikin Alang (or Peudeueng Alang) might be more appropriate?
I'd also be very interested in what hilt types come with L/S/P Alang blades: Any examples around? (I've usually seen them with hulu rumpung.)
Regards,
Kai